Secondary Ridges Research Articles

Giant polygonal anhydrite ridges in the Southern Permian Basin

Giant polygonal anhydrite ridges with diameters of 2−4 km have been identified in the NE margin of the Southern Permian Basin in Poland. The primary ridges reach heights of 80−120 m, and secondary ridges, <40 m in height, subdivide them into smaller cells ∼1 km in diameter. The ridges were up to ∼40% higher before the alteration of gypsum to anhydrite. Both seismic and gravity surveys indicate the presence of similar structures over an area of thousands of square kilometers. Two alternative hypotheses, gypsum diapirism and free water convection, are proposed to explain their formation.

Holocene aeolian environmental dynamics in fixed and semi-fixed deserts over the arid Central Asia revealed by comprehensive sand-dune records

Fixed and semi-fixed deserts are widely distributed in arid Central Asia (ACA). Environmental changes in these deserts can affect the regional radiation balance, climate dynamics, and global climate through a series of feedback effects. This study analyzed luminescence dating from 37 sites, with a particular focus on dendritic dunes (a pattern of vegetated linear dunes) and the ancient dunes beneath them in the Gurbantunggut Desert and yielded the following insights. (1) Primary ridges of dendritic dunes originated approximately 1.0 ka, whereas secondary ridges predominantly formed at 8.5 ± 0.3 ka. The formation of the underlying ancient dunes commenced at least 11.0 ± 0.5 ka and ended between 8.5 ± 0.3 ka and 8.2 ± 0.4 ka. (2) During the Holocene, the Gurbantunggut Desert underwent two distinct environmental phases. From 11.7 ka to 8.1 ± 0.1 ka, the region was characterized by vigorous aeolian activity, marked by the prevalence of mobile dunes. Conversely, the period from 8.1 ± 0.1 ka to 0 ka exhibited substantial environmental amelioration, with limited aeolian activity and the intermittent partial development of vegetated linear dunes. (3) A comprehensive analysis of the principal factors affecting regional aeolian activity revealed that at 11.7 ka–8.1 ± 0.1 ka, moisture (precipitation) and near-surface wind intensity primarily governed aeolian activity in the Gurbantunggut Desert. At 8.1 ± 0.1 ka–0 ka, aeolian activity was mainly influenced by moisture (precipitation), near-surface wind intensity, and external sand supply. (4) Similar patterns of Holocene aeolian activity were observed in the fixed Bayanbulak, Karakum, and Kizil Kum Deserts within the ACA. On a suborbital scale, winter insolation served as the primary driving factor, along with the ice volume and atmospheric CO2 concentration. These factors collectively controlled regional winter temperatures, which determined moisture (precipitation) and near-surface wind intensity by affecting the winter westerlies and Siberian High, ultimately controlling regional aeolian activity.

Computed tomographic investigation of a hatchling skull reveals ontogenetic changes in the dentition and occlusal surface morphology of Hadrosauridae (Dinosauria: Ornithischia)

CMN 8917 is a small, partial skull of a duck-billed dinosaur from the upper Campanian DinosaurPark Formation in what is now Dinosaur Provincial Park, Alberta. It represents one of the few nestling-sized juvenile hadrosaurines known to date. Support for this phylogenetic placement includes a narial vestibule not enclosed within the premaxillary dorsal and lateral processes, the presence of an anterodorsal maxillary process, and a maxillary dorsal process that is longer anteroposteriorly than dorsoventrally. The skull also possesses tooth traits traditionally associated with lambeosaurines, such as secondary ridges on some maxillary and dentary tooth crowns, and denticulation on some maxillary tooth crowns. The occurrence of these features in a juvenile hadrosaurine suggests that they were modified during ontogeny, calling into question their taxonomic utility for identifying juvenile specimens. The dentary teeth of CMN 8917 are similar to those of many adult hadrosaurids in that they possess a concave occlusal surface with steeper lingual and shallower buccal wear zones. This differs from the occlusal surface morphology present in some other juvenile hadrosaurids, which suggests interspecific differences in dental battery development—possibly reflective of dietary differences—occurred during early ontogeny in some taxa.

An early-diverging iguanodontian (Dinosauria: Rhabdodontomorpha) from the Late Cretaceous of North America.

Intensifying macrovertebrate reconnaissance together with refined age-dating of mid-Cretaceous assemblages in recent decades is producing a more nuanced understanding of the impact of the Cretaceous Thermal Maximum on terrestrial ecosystems. Here we report discovery of a new early-diverging ornithopod, Iani smithi gen. et sp. nov., from the Cenomanian-age lower Mussentuchit Member, Cedar Mountain Formation of Utah, USA. The single known specimen of this species (NCSM 29373) includes a well-preserved, disarticulated skull, partial axial column, and portions of the appendicular skeleton. Apomorphic traits are concentrated on the frontal, squamosal, braincase, and premaxilla, including the presence of three premaxillary teeth. Phylogenetic analyses using parsimony and Bayesian inference posit Iani as a North American rhabdodontomorph based on the presence of enlarged, spatulate teeth bearing up to 12 secondary ridges, maxillary teeth lacking a primary ridge, a laterally depressed maxillary process of the jugal, and a posttemporal foramen restricted to the squamosal, among other features. Prior to this discovery, neornithischian paleobiodiversity in the Mussentuchit Member was based primarily on isolated teeth, with only the hadrosauroid Eolambia caroljonesa named from macrovertebrate remains. Documentation of a possible rhabdodontomorph in this assemblage, along with published reports of an as-of-yet undescribed thescelosaurid, and fragmentary remains of ankylosaurians and ceratopsians confirms a minimum of five, cohabiting neornithischian clades in earliest Late Cretaceous terrestrial ecosystems of North America. Due to poor preservation and exploration of Turonian-Santonian assemblages, the timing of rhabdodontomorph extirpation in the Western Interior Basin is, as of yet, unclear. However, Iani documents survival of all three major clades of Early Cretaceous neornithischians (Thescelosauridae, Rhabdodontomorpha, and Ankylopollexia) into the dawn of the Late Cretaceous of North America.

Aeolian disruption and reworking of TARs at the Zhurong rover field site, southern Utopia Planitia, Mars

Aeolian bedforms are the signatures of wind interaction with unconsolidated, granular surface materials. Transverse aeolian ridges (TARs) are widely distributed on Mars but their formation remains enigmatic. China's Zhurong rover explored four crescent-shaped TARs, with two horns generally facing south, during the first 107 sols in southern Utopia Planitia, Mars. Rover images show that these bedforms have distinct light and dark variations on their surfaces that likely result from the combination of a bimodal distribution of particle sizes and the crust formed by the accumulation of aeolian dust. Two of these bedforms exhibit erosional forms on their west sides, where megaripples facing in a direction different from that of the crescentic bedforms they disrupt were created by more recent winds from the northeast. Differing erosional configurations of each of these bedforms in close proximity to each other are probably related to the angle between the bedform crest and the wind direction, and may further suggest that erosion of TARs starts from their two flanks. Secondary ridges of TARs widely recognized on Mars could be megaripples formed during this erosion process. At the Zhurong landing site, TARs degraded into megaripples, suggesting that they might share similar formation and evolution mechanisms there and elsewhere on Mars.

Rare juvenile material constrains estimation of skeletal allometry in Gryposaurus notabilis (Dinosauria: Hadrosauridae).

In studying the skeletal allometry of any vertebrate, it is important to sample the ontogenetic extremes to ensure the accuracy of parameter estimation; this is particularly true for fossil taxa, where sampling of ontogenetic series is incomplete and sporadic. Previous studies have examined allometry in the skull of the duck-billed dinosaur Gryposaurus notabilis, but these did not include individuals smaller than ~65% the maximum known size (based on linear dimensions). Here, we report on the two smallest known examples of this species (a mostly complete skeleton and a partial skull), which are ~37% the known maximal size of G. notabilis. Osteohistology indicates that these represent individuals ~2 years of age. Allometric analysis demonstrates that most aspects of the skull of G. notabilis grew isometrically, although the height of the nasal arch grew with positive allometry. Early in the ontogeny of G. notabilis, the dentary teeth possessed secondary ridges, which were lost later in life. This finding has important bearing on hadrosaurid tooth taxonomy. The limb proportions of G. notabilis largely grew isometrically (or with weak negative allometry, at most), like some other hadrosaurids, suggesting that the species did not undergo a gait shift with increasing age (unless it occurred very early in ontogeny). We argue that the lack of significant locomotory performance compensation exhibited by young hadrosaurids helps to explain why they apparently formed small, mutualistic aggregations, presumably for protection from large predators.

Networked configurations as an emergent property of transverse aeolian ridges on Mars

Transverse aeolian ridges – enigmatic Martian features without a proven terrestrial analog – are increasingly important to our understanding of Martian surface processes. However, it is not well understood how the relationships between different ridges evolve. Here we present a hypothesis for the development of complex hexagonal networks from simple linear forms by analyzing HiRISE images from the Mars Reconnaissance Orbiter. We identify variable morphologies which show the presence of secondary ridges, feathered transverse aeolian ridges and both rectangular and hexagonal networks. We propose that the formation of secondary ridges and the reactivation of primary ridge crests produces sinuous networks which then progress from rectangular cells towards eventual hexagonal cells. This morphological progression may be explained by the ridges acting as roughness elements due to their increased spatial density which would drive a transition from two-dimensional bedforms under three-dimensional flow conditions, to three-dimensional bedforms under two-dimensional flow conditions.

Wear patterns and dental functioning in an Early Cretaceous stegosaur from Yakutia, Eastern Russia.

Isolated stegosaurian teeth from the Early Cretaceous high-latitude (palaeolatitude estimate of N 62°- 66.5°) Teete locality in Yakutia (Eastern Siberia, Russia) are characterized by a labiolingually compressed, slightly asymmetrical and mesiodistally denticulated (9–14 denticles) crown, a pronounced ring-like cingulum, as well as a “complex network of secondary ridges”. The 63 teeth (found during on-site excavation in 2012, 2017–2019 and screen-washing in 2017–2019) most likely belong to one species of a derived (stegosaurine) stegosaur. Most of the teeth exhibit a high degree of wear and up to three wear facets has been observed on a single tooth. The prevalence of worn teeth with up to three wear facets and the presence of different types of facets (including steeply inclined and groove-like) indicate the tooth-tooth contact and precise dental occlusion in the Teete stegosaur. The microwear pattern (mesiodistally or slightly obliquely oriented scratches; differently oriented straight and curved scratches on some wear facets) suggest a complex jaw mechanism with palinal jaw motion. Histological analysis revealed that the Teete stegosaur is characterized by relatively short tooth formation time (95 days) and the presence of a “wavy enamel pattern”. Discoveries of a “wavy enamel pattern” in the Teete stegosaur, in a Middle Jurassic stegosaur from Western Siberia, and in the basal ceratopsian Psittacosaurus, suggest that this histological feature is common for different ornithischian clades, including ornithopods, marginocephalians, and thyreophorans. A juvenile tooth in the Teete sample indicates that stegosaurs were year-round residents and reproduced in high latitudes. The combination of high degree of tooth wear with formation of multiple wear facets, complex jaw motions, relatively short tooth formation time and possibly high tooth replacement rates is interpreted as a special adaptation for a life in high-latitude conditions or, alternatively, as a common stegosaurian adaptation making stegosaurs a successful group of herbivorous dinosaurs in the Middle Jurassic–Early Cretaceous and enabeling them to live in both low- and high-latitude ecosystems.

Boulder Ridges and Washover Features in Galway Bay, Western Ireland

ABSTRACT Erdmann, W.; Kelletat, D., and Kuckuck, M., 2017. Boulder ridges and washover features in Galway Bay, Western Ireland. Boulder deposits of the Aran Islands in the Galway region (western Ireland) have been under investigation for more than 10 years, whereas marine and littoral deposits inside Galway Bay have only been mentioned cursorily. The aim of this study is to investigate all coastal deposits along the most exposed bay coasts from the opening of South Sound to Black Head 25 km inside Galway Bay. Long ridges with imbricated large boulders exist near the surf belt, whereas boulder deposits in clifftop positions are mostly chaotic. The size of individual boulders is similar to those on the exposed island sites of the Aran archipelago. Landward of boulder ridges, stratified fine sediments occur that point to quiet sedimentary conditions. Two more forms and deposits are mapped that are rarely mentioned for western Europe: boulder ridges with crossway secondary ridges and tonguelike washover depos...

Development of NUFORM3D module with FRAPCON3.4 for simulation of pellet-cladding mechanical interaction

In order to evaluate the PCMI (pellet-to-cladding mechanical interaction) behavior in fuel rods, a three-dimensional finite element (FE) module, termed NUFORM3D, was developed by KAERI. In the NUFORM3D module, a thermo-mechanical model considering elasto-plastic deformation and a contact model were formulated to simulate the PCMI behavior. The NUFORM3D module was implemented to compensate for the weaknesses of the analytical methods used in traditional fuel performance codes for PCMI simulations. In this work, NUFORM3D was coupled with FRAPCON-3.4, which is the NRC’s fuel performance code for a steady state, to evaluate the NUFORM3D module with an irradiated database. The REGATE experiment, involving the use of a power ramp database in a test reactor, was employed to evaluate the coupled code system. The coupled NUFORM3D was able to simulate bamboo-shaped deformation of cladding as well as stress concentrations in cladding due to pellet hourglass deformation in the power ramp. Secondary ridges of the cladding on the mid-pellet plane were found in the experimental results. To simulate the secondary ridge, a transversally fragmented pellet model was adopted. As a result, the coupled NUFORM3D module can improve the simulation capability of fuel performance codes for PCMI.

Unravelling raked linear dunes to explain the coexistence of bedforms in complex dunefields

Raked linear dunes keep a constant orientation for considerable distances with a marked asymmetry between a periodic pattern of semi-crescentic structures on one side and a continuous slope on the other. Here we show that this shape is associated with a steady-state dune type arising from the coexistence of two dune growth mechanisms. Primary ridges elongate in the direction of the resultant sand flux. Semi-crescentic structures result from the development of superimposed dunes growing perpendicularly to the maximum gross bedform-normal transport. In the particular case of raked linear dunes, these two mechanisms produces primary and secondary ridges with similar height but with different orientations, which are oblique to each other. The raked pattern develops preferentially on the leeward side of the primary ridges according to the direction of propagation of the superimposed bedforms. As shown by numerical modelling, raked linear dunes occur where both these oblique orientations and dynamics are met.

Geomorphologic patterns of dune networks in the Tengger Desert, China

Dune networks are widely distributed in the world’s deserts, which include primary ridges and secondary ridges. However, they have not been sufficiently studied in a systematic manner and their origins and spatial and morphological characteristics remain unclear. To provide information on the geomorphology of dune networks, we analyze the software geomorphologic patterns of the dune networks in China’s Tengger Desert using matrix and laboratory to process remote-sensing images. Based on analysis of image features and their layout in a topographic map, we identify two types of dune networks (square and rectangular dune networks) with different size and morphological structures in the Tengger Desert. Four important geomorphic pattern parameters, ridge length, spacing, orientation and defect density, are analyzed. The length of primary ridges of dune networks decreases from northwest of the desert to the southeast, resulting an increasing spacing and a transition from rectangular dune networks to square dune networks. Wind regime and sediment supply are responsible for the variation in pattern parameters. We use the spacing and defect density data to estimate the construction time of dune networks and found that the dune networks in the Tengger Desert formed since about 1.3 ka BP.

Phylogeny of Apiaceae subtribe Daucinae and the taxonomic delineation of its genera

AbstractScandiceae subtribe Daucinae encompasses umbellifers that have fruits with prominent secondary ridges projecting into wings (former tribe Laserpitieae) or spines (former tribe Caucalideae pro parte). It comprises several economically or medicinally important genera including Cuminum, Daucus, Laser, Laserpitium and Thapsia among others. Recent molecular studies, based mostly on nrDNA ITS sequences, revealed that neither Daucus nor Laserpitium are monophyletic. To address issues of relationships and apply respective nomenclatural changes, we obtained additional ITS sequences as well as independent data from three plastid markers—rps16 intron, rpoC1 intron and rpoB‐trnC intergenic spacer—for a comprehensive sample of the subtribe. We examined data for 260 accessions representing all genera of Daucinae and 81 of its ca. 93 species. Phylogenetic trees were estimated using maximum likelihood and Bayesian inference methods. The results indicate that former Laserpitieae constitute a paraphyletic grade at the base of the spiny‐fruited members of Daucinae while traditionally delimited Daucus and Laserpitium are polyphyletic. To maintain a monophyletic Daucus, we suggest including the following genera and species into its synonymy: Agrocharis, Melanoselinum, Monizia, Pachyctenium, Pseudorlaya, Rouya, Tornabenea, Athamanta dellacellae and Cryptotaenia elegans. The species of Laserpitium occur in seven clades and only six species of the Laserpitium s.str. clade retain the generic name. Several species are transferred to Ekimia, Laser and Thapsia; additionally, a monospecific genus Siler is restored and a new genus, Silphiodaucus, is established. The inclusion of Ammodaucus into Thapsia suggested in an earlier study is not supported. The position of Laserpitium pseudomeum requires further study.

Evidence of iguanodontian dinosaurs from the Lower Cretaceous of Tunisia

The fossil record of ornithischian dinosaurs from Africa is particularly scarce and limited to a few historic localities. In this study we describe new ornithischian remains from the Albian deposits of southern Tunisia (Tataouine Governorate), represented by isolated teeth of large-bodied iguanodontians. Teeth display a wide, diamond-shaped crown with a primary ridge dividing the occlusal surface in two unequal parts and two or more secondary ridges. Hook-like denticles are present on both mesial and distal crown margins and do not display mammillae. In overall morphology, specimens are comparable to those of many Early Cretaceous basal hadrosauriforms, including isolated ornithopodan teeth from comparably-aged levels of Niger. Transversal sections of the crowns permitted identification of dental tissues, which include a thick enamel, and well developed longitudinal and transverse giant tubules. Their relative extents appear to be related to the size, thus developmental age, of the tooth. Teeth are representative of the Oum ed Diab Member, a unit characterized by coastal deposits accumulated under arid to xeric climatic conditions and dominated by fish, crocodilians, and hydraulically transported rebbachisaurid and spinosaurid remains. Sedimentological data and preservation bias strongly support selective taphonomic causes for the fossil distribution of ornithischians in southern Tunisia questioning the purported geographic and paleoecologic distribution of isolated Saharan dinosaurs.

A New Basal Hadrosauroid Dinosaur from the Lower Cretaceous Khok Kruat Formation in Nakhon Ratchasima Province, Northeastern Thailand.

A new basal hadrosauroid dinosaur from the Lower Cretaceous Khok Kruat Formation of Thailand, Sirindhorna khoratensis gen. et sp. nov is described. The new taxon is based on composite skull and mandible including premaxilla, maxilla, jugal, quadrate, braincases, predentary, dentaries, surangular, and maxillary and dentary teeth. It is diagnostic by such characters as, sagittal crest extending along entire dorsal surface of the parietal and reaching the frontoparietal suture (autapomorphy), transversely straight frontoparietal suture, caudodorsally faced supraoccipital, no participation of the supraoccipital in the foramen magnum, mesiodistally wide leaf-shaped dentary tooth with primary and secondary ridges on the lingual surface of the crown, perpendicularly-erected and large coronoid process of dentary, and nonvisible antorbital fossa of the maxilla in lateral view. Phylogenetic analysis revealed S. khoratensis as among the most basal hadrosauroids. Sirindhorna khoratensis is the best-preserved iguanodontian ornithopod in Southeast Asia and sheds new light to resolve the evolution of basal hadrosauriforms.

Molecular phylogeny of Daucus (Apiaceae): Evidence from nuclear ribosomal DNA ITS sequences

The Apiaceae genus Daucus consists of approximately 25 species (including carrots) which are characterized by the presence of bracts in pedunculate umbels, dorsally compressed mericarps, hairs on primary ridges, and uniseriately arranged spines on the secondary ridges of the fruit. Taxonomically, Daucus has been considered to be one of the most problematic genera in the Apiaceae due to the highly variable fruit morphology. Despite taxonomic controversy and economic importance of the genus, no rigorously constructed estimate of phylogenetic relationships exists. To examine generic limit and relationships among species of Daucus and its putatively related taxa, phylogenetic analyses of characters derived from nuclear ribosomal DNA ITS sequences were conducted. Two major clades emerged within Daucus, but neither of them have been previously recognized using morphological characters. The phylogeny also provides taxonomic status of recently reported new species of Daucus, D. arcanus and D. conchitae.

The first record of a neonatal ornithopod dinosaur from Gondwana

Discrete post-embryonic teeth and bone fragments have been recovered from the matrix with the holotype skeleton (MPM‐10001) of the ornithopod dinosaur, Talenkauen santacrucensis Novas et al., 2004 (Upper Cretaceous, Argentina). The minute tooth crowns are 1mm apicobasally tall and 1.7mm mesodistally wide. The crowns are symmetrical and have a centrally located primary ridge on the lingual surface. Secondary ridges lead to five marginal denticles on both teeth. The tooth morphology is consistent with dentary teeth in euiguanodontids. There is no evidence of transport, suggesting that the material is autochthonous with respect to the adult body block of T. santacrucensis (MPM‐10001). Steeply inclined wear facets on the lingual surface and associated microstriae support the conclusion that the minute teeth were from a post-embryonic euiguanodontid dinosaur rather than early stage replacement teeth. The morphology, size, and wear of the teeth and small bone fragments found in the body block of MPM‐10001 suggest that this material belongs to a neonatal T. santacrucensis. This is the first record of neonatal ornithopod remains from Gondwana.

Microvascularization on Collared Peccary Placenta: A Microvascular Cast Atudy in Late Pregnancy

The microvascularization of the collared peccary (Tayassu tajacu) placenta was studied by vascular casts and immunolocalization of α-smooth muscle actin and vimentin, to identify the three dimensional organization and vascular flow interrelation in the microvasculature between the maternal and fetal compartments of the placentae. The immunolocalization of vimentin in the vascular endothelium and in the smooth muscle cells of blood vessels showed indented capillaries along the uterine epithelium and the trophoblast at the sides of complementary maternal and fetal microfolds, or rugae. This confers the three-dimensional structure observed in vascular casts. On the maternal side, casts demonstrated uterine folds coated by with primary and secondary ridges, and by areolae dispersed between these ridges. The arteriole runs through the center/middle of ridges, branching at the top into a microvascular network wall in a basket-like fashion. At the base of these baskets venules were formed. On the fetal side, arterioles branched centrally in the fetal rugae into a capillary network in a bulbous form, complementary to the opposite maternal depressions forming the baskets. At the base of the bulbous protrusions, the fetal venules arise. The blood vessel orientation in the materno-fetal interface of the placentae of collared peccaries suggests a blood flow pattern of the type countercurrent to cross current. The same pattern has been reported in domestic swine demonstrating that, even after 38 million years, the Tayassuidae and Suidae families exhibit similar placental morphology, which is here characterized at the microvascular level.

Standardisation of Ammi visnaga L. fruit - A homoeopathic drug

Ammi visnaga L. is an annual herb belonging to the family Apiaceae. The dried ripe fruits of this plant are powerful bronchial antispasmodic, cures asthma, besides a strong photosensitiser. The fruit is small, 2 - 2.5 mm in diameter, oval or ellipsoid to lanceolate; each mericarp in transection appears as a pentagon; vittae are present in the secondary ridges; primary ridges possess glandular lacunae; endosperm is enclosed by a testa; aleurone grains are present in the endosperm besides a few sphaeraphides. The powder microscopic and organoleptic characters are provided. Physico-chemical parameters of raw drug viz., extractive values, ash values, formulation, besides weight per ml., total solids, alcohol content along with Thin Layer Chromatographic (TLC) and Ultra Violet Spectroscopic (UV) studies have been undertaken for mother tincture.

Uniqueness of the palatine rugae (ridges) - morphological analysis

The transverse palatine rugae (PR) are asymmetrical and irregular folds of the anterior one third of the palatine mucosa. The PR were considered relevant for the human identification, due to their stability, similar to the fingerprints; their study is identified as palatoscopy. The aim of this study is to describe the shape and the biometrical characteristics of the palatine ridges. We evaluated 72 adult subjects, of which 64 were dentate and 8 edentate. Each patient was imprinted at the level of the upper jaw. Each cast was analyzed in terms of total number of ridges, number of primary, secondary and fragmented ridges, shape, unification and direction. In terms of total number of ridges, the smallest number of ridges was 6, and the largest 18. A feature of the dentate group was the asymmetry of the ridges, only 12 showed paired ridges. Among the non-dentate group we noticed that the total number of ridges is higher in females than in males. The length of the palatine ridges is mainly of a primary type, followed by the secondary type and the fragmentary one. What differentiates the sexes in this case is the number of fragmentate ridges, predominant within female patients. Concerning the shape of the palatine rugae, we noticed, among all the age groups that the linear ridges are predominant, followed by the wavy, curved, angular, punctiform and circular type. Regarding the orientation and the unification of the ridges, we noticed similarities between males and females. The only aspect that may differentiate them is the variety of shapes and their number, which gives them individuality. The palatine rugae are paired only in a small proportion in our study, 19% versus 81%. The length is mainly primary type, regardless of sex, age or degree of edentation. The large number of fragmented ridges is typical to females. The individuality of each ridge drawing is certain as long as we did not encounter identical models.